content: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2012, by Object Refinery Limited and Contributors.
   *
   * Project Info:  http://www.jfree.org/jfreechart/index.html
   *
   * This library is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA.
   *
   * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
   * Other names may be trademarks of their respective owners.]
   *
   * ----------------------
   * AbstractXYDataset.java
   * ----------------------
   * (C) Copyright 2004-2008, by Object Refinery Limited.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited).
   * Contributor(s):   -;
   *
   * Changes
   * -------
   * 05-May-2004 : Version 1 (DG);
   * 15-Jul-2004 : Switched getX() with getXValue() and getY() with
   *               getYValue() (DG);
   * 18-Aug-2004 : Moved from org.jfree.data --> org.jfree.data.xy (DG);
   *
   */
  
  package org.jfree.data.xy;
  
  import org.jfree.data.DomainOrder;
  import org.jfree.data.general.AbstractSeriesDataset;
  
  /**
   * An base class that you can use to create new implementations of the
   * {@link XYDataset} interface.
   */
  public abstract class AbstractXYDataset extends AbstractSeriesDataset
          implements XYDataset {
  
      /**
       * Returns the order of the domain (X) values.
       *
       * @return The domain order.
       */
      @Override
      public DomainOrder getDomainOrder() {
          return DomainOrder.NONE;
      }
  
      /**
       * Returns the x-value (as a double primitive) for an item within a series.
       *
       * @param series  the series index (zero-based).
       * @param item  the item index (zero-based).
       *
       * @return The value.
       */
      @Override
      public double getXValue(int series, int item) {
          double result = Double.NaN;
          Number x = getX(series, item);
          if (x != null) {
              result = x.doubleValue();
          }
          return result;
      }
  
      /**
       * Returns the y-value (as a double primitive) for an item within a series.
       *
       * @param series  the series index (zero-based).
       * @param item  the item index (zero-based).
       *
       * @return The value.
       */
      @Override
      public double getYValue(int series, int item) {
          double result = Double.NaN;
          Number y = getY(series, item);
          if (y != null) {
              result = y.doubleValue();
          }
          return result;
      }
  
  }
  